Functional neuroimaging in the study of aggressive behaviour in patients with schizophrenia

Introduction. Although aggressive behaviours are not always very highly prevalent in schizophrenia, their occurrence does represent a significant problem for patients and those around them. Although neuroimaging studies have made it possible to further our knowledge of the biology of these behaviours, there is still a notable degree of clinical heterogeneity in the study samples that makes it difficult to obtain conclusive results that can be compared with each other. Aim. To determine whether there are variations in the brain activity, as measured with functional magnetic resonance imaging, of a homogenous group of patients with schizophrenia and aggressive behaviour. Patients and methods. The sample consisted of 32 patients with refractory schizophrenia and auditory hallucinations selected for the study. The subjects were submitted to a functional magnetic resonance imaging examination using an auditory paradigm with emotional stimulation, while the degree of aggressiveness was measured by means of the Brief Psychiatric Rating Scale. Results. Significant correlations were found between functional activation and the degree of aggressiveness, which show focal hyperactivations in patients with a greater association to violent behaviours. The areas identified were located in the left hippocampus (p < 0.003, corrected) and in the right medial frontal gyrus (p < 0.004, corrected). Conclusions. This study determines the association between the degree of aggressiveness and certain regions in the brain that are responsible for cognitive and emotional processing in a phenotypically very homogenous group of patients with chronic auditory hallucinations and schizophrenia. This alteration of the neuronal circuits can favour loss in the processes involved in empathy and sensitivity, thus favouring the appearance of aggressive behaviours.